A conventional motor grader comprises a blade adapted to be moved and held in a selected position of operation by at least one cylinder. The cylinder is integrated into a fluid circuit, including a lockout valve adapted to trap fluid in the rod and head ends of the cylinder during such operation. The cylinder thus functions to hold the blade in a semi-rigid position on the motor grader during a finish grading operation, for example.
It is oftentimes desirable to employ the blade or other auxiliary work tool mounted on the motor grader for an additional operation, such as snow removal. During the latter operation, it is desirable to "float" the blade by providing means in the fluid circuit whereby a degree of reciprocal movement is provided by the cylinder. For example, U.S. application Ser. No. 356,362, filed on May 2, 1973 by Joseph E. Dezelan et al for "Selectively Actuatable Shock Absorbing System For An Implement Control Circuit," discloses the utilization of shock absorbing means in the form of a pair of accumulators operatively connected to the cylinder to achieve a degree of "floating." Such application, assigned to the assignee of this application, is now U.S. Pat. No. 3,872,670.